Encapsulated, particle-based displays offer a useful means of creating electronic displays. There exist many versions of encapsulated particle-based displays including encapsulated electrophoretic displays, encapsulated suspended particle displays, and rotating ball displays.
Encapsulated, particle-based displays can be made highly reflective, bistable, and optically and electrically efficient. To obtain a high-resolution display, however, individual pixels of a display must be addressable without interference from adjacent pixels. One way to achieve this objective is to provide an array of nonlinear elements, such as transistors or diodes where each transistor or diode is associated with each pixel. An addressing electrode is connected to each pixel through the transistor or the diode.
The processes for manufacturing active matrix arrays of thin-film transistors and diodes are well established in the display technology. Thin-film transistors, for example, can be fabricated using various deposition and photolithography techniques. A transistor includes a gate electrode, an insulating dielectric layer, a semiconductor layer and source and drain electrodes. Application of a voltage on the gate electrode provides an electric field across the semiconductor layer, which dramatically increases the source-to-drain conductivity of the semiconductor layer. This change allows for electrical conduction between the source and the drain electrodes. The gate electrode, the source electrode, and the drain electrode are typically patterned. In general, the semiconductor layer and the gate dielectric layer are also patterned in order to minimize stray conduction (i.e., cross-talk) between neighboring circuit elements. Following these steps, thin-film transistors can be fabricated to provide high performance. These processes, however, can result in significant cost.
The high cost in manufacturing thin-film transistors results in part from the patterning steps, which require the use of expensive masks in photolithographic setups, and etching steps. Trends toward making higher performance devices make precision patterning even more important and manufacturing cost even greater.
Certain electronic devices, however, do not require high performance while cost remains very important. For such devices, it remains desirable to have means to obtain better yield and lower of cost of manufacturing.